Air compressor



June 13, 1939. R. E. LAMBERTON AIR COMPRESSOR Filed Dec. 27, 1935 Add-M m Patented June 13, 1939 2,161,828

UNITED stares PATENT OFFICE AIRCOMPRESSOR Ralph E. Lamberton, Michigan City, Ina, assignor to Sullivan Machinery Company, a corporation of Massachusetts Application December 27, 1935, Serial No. 56,357

.Claims. (Cl. 230--30) This invention relates to air compressors-and tion there is shown an air compressor of the pumps, and more particularly to an improved Vertical cylinder type, although it will be evident and more efficient intake flow passage arrangethat the improved air passage arrangement and ment associated with the inlet valve means and associated unloading mechanism may be em- 5 improved compressor unloading mechanism bodied in air compressors of various other types.

whereby, due to streamlining, a smooth flow of The compressor shown herein comprises a cylinair to the compressor intake is assured. der containing a reciprocatory piston 2 con- In most air compressors and pumps using inletnected to any appropriate reciprocating means. valve opening as the method ofunloading, the in- Supported at the top of the cylinder is apair of take passage means associated with the inlet valve cage forming plates3and4 secured together 1 valve mechanism and the unloading mechanism, in superimposed relation by a center screw 5, the due to the particular location and design of the latter having a head contacting with a washer unloading mechanism, necessarily have had p-roengaging the upper surface of the top plate 3 jections, both on the unloading elements and the and having a shank passing through an opening associated casing, protruding into the path of in the top plate into threaded engagement with air flow, and due to this, and to the irregular the bottom plate 4, so that the lower end of the shape and 'tortuousness of the intake passages, screw is substantially flush with the bottom surfiow has been restricted and eddy currents have face of the bottom plate. The valve cage plates been produced, thereby materially further imare held in position on the top of the cylinder peding the flow, and, as a result, compressor efiiby means of a cylinder head 6 secured to the 80 ciency has been quite materially decreased. cy as y means of ts s cured to An object of the present invention is to provide the top surface of the head as by bolts 8 is a supan improved flow'passage arrangement for the plemental head 9, the bolts 8 passing through compressor or pump intake whereby a relatively openings in the'head bosses and valve plate 3 smooth and free flow of air to the inlet valve into threaded engagement with the lower valve 25 means is attained. Another object is to provide plate s in the manner shown. In accordance in a compressor or pump an improved: unloading with the usual practice. sealing gaskets are intermechanism of the inlet valve type and an imposed between the joining surfaces of the various proved flow passage arrangement associated parts to prevent leakage. If desired, the suppletherewith whereby a relativelyireeand smooth mental head may be formed integral with the flow of air, past the unloading mechanism, to the cylinder head, although for manufacturing purcompressor inlet valve is attained during loaded poses separate heads are more practical.

operation and whereby, during unloaded opera- The valve cage plate assembly is herein of the tion, as little power is used aspossible during Combined inlet and discharge type, the lower the rapidly alternated drawing'in and forcing plate having formed in its upper surface an anout of air relative to the, compressor cylinder. nular recess H formin the ve c amber for A further object is; to provide. an improved the inlet valve, while the lower surface of the top tr mlin flow assa arrangement for the plate 3 has formed therein an annular recess l2 intake of an air compressor or pump. 'I'h nd forming a valve chamber for the discharge valve.

40 other objects and advantages'of the invention Formed in the bottom plate is a series. of arcu- 40 will, however, hereinafter more fully appear. ate discharge passages l3 communicating with In the accompanying drawing there is shown the valve chamber 12, while formed in the top for purposes of illustration one form which the p te 3 s a Series O archaic inlet passages l4 invention may assume in practice. for the valve chamber II. In accordance with In this drawing,- V the usual practice, the sides of the inlet valve Fig. 1 is a vertical sectional view taken chamber H communicate as at l5 with inlet pasthrough a compressor cylinder and cylinder head a es in the ower plate 4, While the upper plate and the associated inlet valve means and un- 2-3 is likewise formed with slots l6 communicating loading mechanism, constructed in accordance with the valve chamber I2 to provide discharge 5 with one illustrative form of'theinvention. passages a ed n t e et chamber II is Fig. 2 is a cross sectional viewtak'en substanan annular plate valve I! held in seated position tially on line 22 of Fig. 1. j i against the lower face of the top plate 3 by means Fig. 3 is a perspective View lof an unloading or aspring I8, and this valve controls the flow of plunger, air from the inlet passages [4 through the Valve '55 In this illustrativeembodiment oi-th'e invenchamber and the slots Hi to the compressor cylin- .55

r in the cap with the upper end of the cylinder der. Arranged in the discharge chamber I2 is an annular plate valve I9 held in seated position against the top face of the bottom plate 4 by a 7 spring 20, and this valve controls the flow of compressed air from the cylinder through passages l3 and through the valve chamber to the slots I 6. Formed in the cylinder head is an annular discharge chamber 2| with which the discharge slots lfi communicate and from which thecbmpressed air flows through a communicating downwardly curved passage 22 and registering,

passages 23 and 24 in the plates 3 and 4 respectively, to a discharge passage-25. It will thus be seen that as the compressor piston reciprocates, air at atmospheric pressure is drawn in through the inlet passages l4 and through the valve chamber and slots I to the upper end of the cylinder, and the compressed air is discharged 7 7 from the cylinder through the discharge passages supplemental head 8 is a vertical cylinder 21 having a bore 28 in substantial alinement with the compressor cylinder bore, and this bore 28 contains a reciprocatory piston 28 carrying a usual cup packing 30 to prevent leakage past the piston. Secured within the upper end of the cylinder 21 is a detachable cap 3| having a connection 32 communicating through a passage 33 bor 28 at the upper side of the piston 23. This connection 32 is adapted to be in communication with the compressor discharge pressure un- 'der the control of usual pilot valve means so that i when the compressor'dlscharge pressure exceeds 'a predetermined maximum, air pressure'is conducted, under the control of the pilot valve means, through the connection '32 and passage 7 33 tothe cylinder bore at the upper side of the piston 29 fora purpose to be later mentioned. Formed centrally within the cylinder head is an upstanding cylindrical guide portion 34 having slidingly guided thereon a plunger 35 having a circular plane upper surface 36 with which the lower surface of the piston-23 is engageable In. this instance, the cylindrical vertical walls of,

the plunger 35 guided on the cylindricalportion 34 are connected at their top to the upwardly tapering upper portion of the plungenrwhich has a smooth exterior wall3'l; and formed on the lower portion of the cylindrical guide portion of the plunger are depending fingers 38 projecting through annularly arranged passages V 39' surroundingethe cylindrical bearing portion 34,,

within the inlet passages 14 in the 'top plate 3.

interposed between the upper surface of the 7 guide portion 34 and'the inner surface of-the plunger 35 is a coil spring 48 for constantly urgf ing 'the'plunger toward its uppermost position against the lower surface of the cylinder 21, this spring being centered'on the guide portion by a guide boss and centeredwith respect-to itheplunger by means of an annular guide flange 42 on the plunger; The smooth inner cylindrical surface 43 of the flow passage 39 in the cylinder head and thesmooth cylindrical exterior surface of the plunger 35 cooperate with a curved flow passage 45 in the supplemental headlandthe tapered enterior surface of the converging upper walls of the plunger to provide a smooth streamline flow passage through the supplemental head and the cylinder head to the inlet passages of the inlet valve, all protuberances projecting within the flow path being reduced to a minimum; and in conjunction with this smoothflow passage arrangement, the fingers 38 on the plunger and the strengthening webs 46 in the. a

cylinder head, t l'itlattr ladlhg 156 the cylindrical portion 34, are shaped to obtain a smoothflow of air past the same as the air flows through V the annular flow space 33. Secured, as by bolts,

to the supplemental head is a connection 41 having a passage 48 communicating with the passsgelasn nppcrted within this connection is an air" filter- 49 of a conventional design through V which atmospheric "air'flows to the intake'passage means. As the'cycle of air compression in, a compressor of this type is well known to those skilled in the art, further description of the mode of operation and control is herein considered unnecessary other than to state that air at atmospheric pressure is drawn into the compressor cylinder, compressed, and discharged therefrom; and when the compressor discharge pressure exceeds a predetermined maximum, air

pressure is admitted to the cylinder bore 28 at the upper side of the piston 29 to move the latter downwardly; thereby depressing the unloading plunger 85 to bring the depending fingers 38 thereof into engagement with the inlet valve plate Ilto unseat the latter, thereby to hold the inlet valve'op'en, and as a result; unloading the compressor. When the compressor discharge pressure'drops below a predetermined minimum,

the pressure inthe'cylin'der bore above the piston 29 is vented to atmosphere through the pilot valve means, causing the coilspring 4ll tolift the unloading plunger to its inoperative posi tion, thereby permitting the inlet valve to operate in a normal manner As, a result of this invention, it will be noted that an improved intake passage meansis provided for an air compressor whereby a's'm ooth 7 flow or air to the inlet valve means is attained.

It will further be noted that by associating the intake passage means with elements of the unloading means and by forming the unloading element with smooth exterior surfaces, an extremelysmooth flow of inlet air is obtained past the unloading mechanismto the compressor inlet vane.- Qfiier iiss and advantages Of the invennon win be clearly apparent to those skilled in eai I While there is in this applicationspeciiically described one form which the invention may assume in practice, it willbe ufiderstood that this form or messin is show'n for purposes er i lustrat on and that the invention may be moan fled and embodied-in various other forms with out depa tingfrom its spirit or the scope of the 7 appended Y claliiis'.

What 'I claim as new and desire to secure by Letters f ate'nt' is V 1. In an air compressor, in combination, a,cyl-

inder containing areciprocatory piston, a cylinder head, inlet valve means,-acylindrical guide portion formed 'm said head,a cylindrical unloading plunger guided on said guide portion and having a smooth exterior surface, said plunger adaptedto engage and hold open the inlet valve means to unload the compressor, intake passage means associated with said cylinder head and-including 7 an annular flow passage formed in said head and surrounding said cylindrical plunger, and a sup- 7;

plemental head attached to said cylinder head and having a cylinder containing a piston engageable with said plunger for actuating the latter, said passage means including an intake passage in said supplemental head communicating with said annular flow passage.

2. In a compressor, in combination, a cylinder containing a reciprocable piston, a cylinder head, inlet valve means, a centrally located cylindrical guide portion formed in said head, a cylindrical unloading plunger guided on said guide portion for axial movement with respect thereto and having a smooth exterior periphery, said plunger adapted to engage and hold open said inlet valve means to unload the compressor, a supplemental head at-,

tached to said cylinder head, a cylinder formed in said supplemental head containing a reciprocable piston engageable with said plunger for axially moving the latter, and intake passage means associated with said heads including an annular, smooth-walled flow passage formed in said cylinder head and surrounding said unloading plunger, and a communicating flow passage in said supplemental head.

3. In a compressor, in combination, a cylinder containing a reciprocable piston, a cylinder head, inlet and discharge valve means, a centrally located cylindrical guide portion formed in said head, a cylindrical unloading plunger guided on said guide portion for axial movement with respect thereto and having a smooth exterior periphery, said plunger adapted to engage and hold open said inlet valve means to unload the compressor, a supplemental head attached to said cylinder head, a cylinder formed in said supplemental head containing a reciprocatory piston engageable with said plunger for axially moving the latter, intake passage means associated with said heads including an annular, smooth-Walled fiow passage formed in said cylinder head and surrounding said unloading plunger and a communicating flow passage in said supplemental head, and an annular discharge passage surrounding said intake flow passage and separated therefrom and to which compressed air is discharged from the cylinder through said discharge valve means.

4. In an air compressor, in combination, a cylinder containing a reciprocatory piston, a cylinder head, inlet valve means, a cylindrical guide portion formed in said head, a cylindrical unloading plunger guided on said guide portion and adapted to engage and hold open said inlet valve means to unload the compressor, said plunger having a cylindrical portion of uniform diameter engaging said guiding portion and an upwardly tapering upper portion terminating in a plane circular topsurface, and intake passage means associated with 1 said head including an annular flow passage formed in said head and surrounding said. cylindrical plunger and an elbow-like lateral supply 7 connection mostly above said plunger.

5. In a compressor, in combination, a cylinder containing a reciprocatory piston, a cylinder head,-

inlet valve means, a centrally located cylindrical guide portion formed in said head, a cylindricalunloading plunger guided on said guide portion for axial movement with respect thereto and having a smooth exterior periphery and adapted to engage and hold open said inlet valve means to unload the compressor, said plunger having a cylindrical portion of uniform diameter engaging said guiding portion and an upwardly tapering upper portion terminating in a plane circular top surface, a supplemental head attached to said cylinder head, a cylinder formed in said supplemental head and containing a reciprocatory piston adapted to engage the top plane surface of said plunger for axially moving the latter, and intake passage means associated with said heads and including an annular smooth-Walled flow passage formed in said cylinder head and surrounding said unloading plunger and a communicating flow passage in said supplemental head.

RALPH E. LAIVIBERTON. 

